Welding method and welding appliance for preventing double-layer pipe from cracking during assembly

Abstract

The invention discloses a welding method for preventing a double-layer pipe from cracking during assembly. The welding method comprises the following steps that a, a preliminary fixing structure is formed between an inner pipe A and an outer pipe B through a plurality of welding points; b, a plurality of grooves are formed in an upper flange C or a lower flange D of the inner pipe A, and a straight-through welding tool X is inserted into the grooves; and c, a straight-through welding tool X and a peripheral welding tool Z on the outer side of the outer pipe B are used for welding the joint of the upper flange C or the lower flange D and the outer pipe B. In the welding process, the straight-through welding tool X and the peripheral welding tool Z on the outer side of the outer pipe B work cooperatively, and the inner side and the outer side of the joint of the upper flange C or the lower flange D and the outer pipe B are fused at the same time. And the risks of internal stress and cracking in the welding process can be effectively reduced.

Description

Technical Field

[0001] The invention relates to the technical field of double-layer tube quartz welding processing, in particular to a welding method and welding device for preventing a double-layer tube assembly from instantaneously cracking. Background Art

[0002] The double-layer tube consists of an inner tube A and an outer tube B. The double-layer tube can be combined in various ways, such as Figure 1 The existing combined welding method is as follows: the first step is to determine the relative position of the inner and outer tubes by using an assembly mechanical device; the second step is to spot weld between the inner tube A and the outer tube B; the third step is to pull the material between the inner tube A and the outer tube B; the fourth step is to return to the starting position to melt the solder after a period of pulling and welding, and the melting position can only be on the outside of the outer tube B (single-side melting), and the gun cannot melt on the inside of the outer tube B, that is, between the inner tube A and the outer tube B.

[0003] Another example is "A double-layer vertical quartz tube carrier and its processing method" disclosed in Chinese patent documents, with the announcement number "CN111013515A", which includes an inner tube, an outer tube, a first quartz plate, a second quartz plate, a flange, a first couple tube, a second couple tube, a third couple tube, a vent pipe, a first small flange, a second small flange, and a third small flange. The inner tube is embedded in the outer tube, and the inner tube and the outer tube are fixedly connected together by welding. The gap distance between the inner tube and the outer tube is 15 mm. The first couple tube, the second couple tube, and the third couple tube are fixedly welded to the inner wall of the inner tube, the first small flange, the second small flange, and the third small flange are fixedly welded to the inner tube, the vent pipe is fixedly welded to the inner tube, and a support plate is fixedly welded under the vent pipe.

[0004] In the prior art, when the welding amount is large (the welding thickness is thick or the width is wide), the melting on the outer side of the outer tube B has high technical requirements. If the melting time is long or the welding torch is turned on too high, the weld part will be severely deformed and the product size and appearance requirements will not be met. If the melting time is short or the welding torch is turned on too low, the solder will not be fully melted, so as the temperature drops suddenly, tensile stress will be generated in the unmelted area, causing cracks.

[0005] In addition, since single-sided melting has high requirements for welding and melting technology, correspondingly, it also has high requirements for personnel skills, which limits the output of double-layer pipes and is inefficient. If cracks occur, the rework cycle is long, the cost is high, and it is not conducive to the improvement of production capacity.

[0006] Therefore, it is necessary to optimize the existing solutions to eliminate the above problems. Summary of the invention

[0007] In view of the problem of easy cracking due to single-sided melting in the prior art and how to reduce the requirements for personnel skills and reduce the risk of cracking during welding, the present invention provides a welding method for preventing instant cracking of a double-layer pipe assembly. In addition to melting on the outside of the outer pipe B, the welding gun can also be melted on the inside of the outer pipe B to form double-sided melting, so that the requirements for personnel skills are relatively reduced, and the solder can be fully melted, and no unmelted part will be formed in the welding part. As the temperature decreases, no stress concentration will be generated, thereby greatly reducing the risk of cracking.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions: A welding method for preventing a double-layer pipe assembly from instantaneously cracking, characterized in that it comprises the following steps: a: Use several welding points to form a preliminary fixing structure between the inner tube A and the outer tube B; b: A number of grooves are provided on the upper flange C or the lower flange D of the inner tube A for inserting the straight-through welding tool X; c: Use the straight-through welding tool X and the peripheral welding tool Z on the outside of the outer tube B to weld at the connection between the upper flange C or the lower flange D and the outer tube B.

[0009] In this solution, the quality and efficiency of welding are improved through optimized steps and technical settings. First, the method uses several welding points to form a preliminary fixed structure between the inner tube A and the outer tube B, which provides the necessary stability for the welding process. Secondly, several grooves are opened on the upper flange C or the lower flange D of the inner tube A for inserting the straight-through welding tool X. The design of these grooves allows the tool to penetrate into the internal space of the double-layer tube for precise welding. During the welding process, the straight-through welding tool X works with the peripheral welding tool Z on the outside of the outer tube B to achieve simultaneous melting of the inside and outside of the connection between the upper flange C or the lower flange D and the outer tube B. This bilateral melting technology is the core innovation of the present invention, which can effectively reduce the risk of internal stress and cracking during welding. By heating the inside and outside at the same time, the weld is formed more evenly, thereby improving the quality of the welded joint and the stability of the overall structure.

[0010] Compared with the traditional single-sided welding method, the welding method of the present invention has significant advantages. In the traditional method, single-sided heating may cause uneven heat effects inside the welding area, increasing the risk of cracking. The present invention effectively avoids this problem by welding on both sides at the same time, thereby improving the reliability of welding and the service life of the double-layer pipe.

[0011] In addition, the welding method of the present invention is highly adaptable. Since the number and position of the grooves can be adjusted according to the specific shape and processing technology of the product, the method is not only applicable to circular pipes, but also to the welding of closed or semi-enclosed spaces composed of inner and outer pipes of square, rectangular, special-shaped, etc.

[0012] Preferably, the welding points are evenly distributed between the upper flange C and the outer tube B and between the lower flange D and the outer tube B. The distribution characteristics of the welding points are further clarified, and the even distribution of the welding points helps to ensure the structural stability of the double-layer tube during the welding process. Since the welding points act evenly on the entire welding area, the local stress concentration or deformation caused by the uneven distribution of the welding points is reduced, thereby improving the overall stiffness and deformation resistance of the welded structure. Evenly distributed welding points help to achieve uniform heat transfer, which is crucial to prevent thermal deformation during welding. During the welding process, the concentration of heat may cause uneven expansion and contraction of the material, thereby generating internal stress and cracking. By evenly distributing the welding points, the temperature distribution of the welding area can be more effectively controlled, reducing the risk of thermal deformation and cracking. In addition, evenly distributed welding points also help to improve the quality and consistency of the welded joint. Due to the even distribution of the welding points, the welding material can fill the weld more evenly, thereby improving the integrity and uniformity of the weld, and enhancing the bearing capacity and durability of the welded joint. Compared with the common solution of unevenly distributed welding points, the present invention effectively solves the problems of stress concentration, thermal deformation and inconsistent quality of welded joints that may occur during welding by evenly distributing the welding points.

[0013] Preferably, the welding process includes laying the double-layer pipe flat and then selecting one end for welding.

[0014] Preferably, after completing welding at one end, move to the other end and repeat the same welding steps.

[0015] The welding process begins by laying the double-layer pipe flat and selecting one end for welding. After completing the welding of one end, the double-layer pipe is moved to the other end and the same welding steps are repeated. This method allows the operator to perform the welding work in an orderly manner, ensuring that each end undergoes the same welding process, thereby ensuring the consistency and reliability of the welding quality. The straight-through welding tool X is inserted into the groove of the upper flange C or the lower flange D (step d). Next, the straight-through welding tool X is used to weld from the groove, while the peripheral welding tool Z is used on the outside to form simultaneous melting of the inside and outside (step e). This step is to achieve simultaneous melting of the inside and outside, which helps to improve the strength and quality of the weld while reducing welding stress and potential cracking risks. After welding a section, the straight-through welding tool X is pulled out of the current groove and then inserted into the adjacent groove to continue welding the next section. This segmented welding method not only improves the flexibility of operation, but also makes the welding process more refined and controllable. This welding method achieves effective control of the welding quality of the double-layer pipe through an orderly welding sequence and precise operating steps. The strategy of laying flat for welding and moving sequentially, combined with the technology of simultaneous melting of the inside and outside, not only improves the stability and consistency of welding, but also reduces the risk of cracking by reducing welding stress, thereby improving the overall structural strength and durability of the double-layer pipe.

[0016] Furthermore, the welding process in step c further includes: d: Insert the straight welding tool X into the groove of the upper flange C or the lower flange D; e: Welding is performed from the groove using the straight-through welding tool X, while the peripheral welding tool Z is used on the outside to achieve simultaneous melting of the inside and outside.

[0017] Furthermore, after welding a section, the through welding tool X is pulled out from the current slot and then inserted into the adjacent slot to continue welding the next section.

[0018] This method requires the operator to pull out the straight-through welding tool X from the current slot after welding a section, and then quickly insert it into the adjacent slot to continue welding, thereby achieving an efficient and continuous welding process. This mode of operation not only improves the efficiency of welding, because it reduces the time for tool replacement and repositioning, but also ensures the consistency of welding parameters, which helps to maintain the uniformity and stability of the welded joint. Through segmented welding, the welding area is allowed to cool gradually, which reduces the welding stress concentration that may be caused by rapid overall heating and helps to prevent cracking during welding. In addition, this method provides greater flexibility and controllability, allowing the operator to flexibly adjust the order and progress of welding according to specific welding needs and pipe characteristics. This method is also highly adaptable and suitable for double-layer pipes of different lengths and shapes, because it allows the welding strategy to be adjusted according to the specific conditions of welding. It significantly improves the efficiency of the welding process and the quality of the welded joint, reduces the labor intensity of the operator, and extends the service life of the double-layer pipe.

[0019] Preferably, when welding the upper flange C and the outer pipe B, a curved welding tool Y is used instead of the straight welding tool X. The length and curvature of the curved welding tool Y are selected according to the product diameter and position.

[0020] Furthermore, after welding a section, the curve welding tool Y is pulled out from the current slot and then inserted into the adjacent slot to continue welding the next section.

[0021] This method introduces a curve welding tool Y, the length and curvature of which can be adjusted according to the diameter and position of the product. The use of curve welding tool Y can better adapt to different welding environments, especially in the welding of flange C, it can fit the curve shape of the flange, ensure the uniform distribution of heat during welding, thereby reducing welding stress and improving weld quality. During the welding process, after completing a section of welding, the curve welding tool Y will be pulled out of the current slot, and then quickly inserted into the adjacent slot to continue the next section of welding. This method improves the efficiency and continuity of welding, while maintaining the consistency of welding parameters, ensuring the uniformity and stability of the welded joint. This segmented welding strategy allows the welding area to cool gradually, further reducing welding stress and preventing cracking that may be caused by rapid overall heating.

[0022] In addition, the use of the curved welding tool Y reflects the flexibility and accuracy of the present invention in the field of welding. It is not only suitable for flanges C of different diameters and shapes, but also improves the overall performance and service life of the double-layer pipe by reducing the thermal impact during the welding process.

[0023] The welding tools include a straight welding tool X, a curved welding tool Y and a peripheral welding tool Z. The straight welding tool X and the peripheral welding tool Z have the same structure. The welding tools each include a detachable welding gun tube. The cross section of the welding gun tube includes but is not limited to round, square, rectangular and special shapes.

[0024] The welding tools include straight-through welding tool X, curved welding tool Y and peripheral welding tool Z, which are designed for specific welding tasks. The straight-through welding tool X and the peripheral welding tool Z are designed in the same way, and the designers pursue standardization and interoperability between the tools to simplify the operation process and improve the versatility of the tools. This design allows operators to flexibly switch between different welding applications while maintaining consistency and efficiency in operation. Further, an important feature of the welding tools is that they all include detachable welding gun barrels. This design provides great flexibility and adaptability because the welding gun barrel can be replaced with different cross-sectional shapes such as round, square, rectangular and special shapes according to different welding requirements. This diversity enables the welding tools to adapt to various welding environments and material requirements, thereby expanding their application range. In particular, the introduction of detachable welding gun barrels allows the tools to be optimized according to specific welding tasks, for example, selecting a specific cross-sectional shape to match a specific welding area, or selecting the most suitable welding gun barrel according to the heat conduction characteristics of the welding material. This not only improves welding efficiency, but also helps to ensure the quality of the welded joint and reduce the risk of welding defects. In addition, this detachable design also facilitates the maintenance and cleaning of welding tools, extending the service life of the tools. By simply replacing the welding gun barrel, the operator can quickly switch between different welding tasks without having to replace the entire welding tool, which greatly improves the convenience and economy of operation.

[0025] In particular, the structural features of the curved welding tool Y are crucial in the design of the welding utensil to adapt to different welding needs. The design of this tool allows it to fit the specific shape of the welding area, especially when the welding area is curved or has an irregular shape. The curved shape of the curved welding tool Y is able to reach deep into the welding groove, ensuring the uniformity and continuity of the welding process, especially in scenarios where circumferential welding or welding on curved surfaces is required. The structural design of the curved welding tool Y takes into account the heat distribution during the welding process and the fluidity of the welding material. By optimizing the shape of the tool, it can better control the welding heat and reduce the unnecessary impact of heat on the surrounding materials, thereby reducing the risk of welding deformation and stress. In addition, the curved welding tool Y is able to improve the filling efficiency of the weld because its shape is more suitable for following the welding path and ensuring the uniform formation of the weld. With a variety of welding utensil structures, operators can cope with complex welding tasks more flexibly, whether in straight or curved welding areas.

[0026] Therefore, the present invention has the following beneficial effects: By using a detachable welding gun barrel, it can be quickly replaced according to the welding task, reducing preparation time and improving operational efficiency.

[0027] The curved design of the curved welding tool Y enables it to fit welding areas of complex shapes, expanding the application range of the welding method.

[0028] The curved welding tool Y controls heat transfer through shape optimization, reduces thermal deformation and welding stress, and improves the quality of welded joints.

[0029] The standardized straight-through welding tool X and peripheral welding tool Z design ensures the consistency of different welding points and improves the overall welding quality.

[0030] The detachable welding gun barrel is easy to clean and replace, reducing the difficulty and cost of tool maintenance and extending the service life of welding equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A schematic diagram of the structure of the double-layer tube group processed and formed for this application.

[0032] Figure 2 It is a schematic diagram of the structure of a double-layer pipe group without welded outer pipe B.

[0033] In the figure: 1. inner tube A, 2. outer tube B, 3. upper flange C, 4. lower flange D, 5. groove. DETAILED DESCRIPTION

[0034] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions.

[0035] Example 1 like Figure 1 As shown, the present invention adopts the following technical solutions: A welding method for preventing a double-layer pipe assembly from instantaneously cracking, characterized in that it comprises the following steps: a: Use several welding points to form a preliminary fixing structure between the inner tube A1 and the outer tube B2; b: A plurality of grooves 5 are provided on the upper flange C3 or the lower flange D4 of the inner tube A for inserting the straight-through welding tool X; c: Use the straight-through welding tool X and the peripheral welding tool Z on the outside of the outer tube B to weld at the connection between the upper flange C or the lower flange D and the outer tube B.

[0036] In this solution, the quality and efficiency of welding are improved through optimized steps and technical settings. First, the method uses several welding points to form a preliminary fixed structure between the inner tube A and the outer tube B, which provides the necessary stability for the welding process. Secondly, several grooves are opened on the upper flange C or the lower flange D of the inner tube A for inserting the straight-through welding tool X. The design of these grooves allows the tool to penetrate into the internal space of the double-layer tube for precise welding. During the welding process, the straight-through welding tool X works with the peripheral welding tool Z on the outside of the outer tube B to achieve simultaneous melting of the inside and outside of the connection between the upper flange C or the lower flange D and the outer tube B. This bilateral melting technology is the core innovation of the present invention, which can effectively reduce the risk of internal stress and cracking during welding. By heating the inside and outside at the same time, the weld is formed more evenly, thereby improving the quality of the welded joint and the stability of the overall structure.

[0037] Compared with the traditional single-sided welding method, the welding method of the present invention has significant advantages. In the traditional method, single-sided heating may cause uneven heat effects inside the welding area, increasing the risk of cracking. The present invention effectively avoids this problem by welding on both sides at the same time, thereby improving the reliability of welding and the service life of the double-layer pipe.

[0038] In addition, the welding method of the present invention is highly adaptable. Since the number and position of the grooves can be adjusted according to the specific shape and processing technology of the product, the method is not only applicable to circular pipes, but also to the welding of closed or semi-enclosed spaces composed of inner and outer pipes of square, rectangular, special-shaped, etc.

[0039] like Figure 2As shown, the welding points are evenly distributed between the upper flange C and the outer tube B and between the lower flange D and the outer tube B. The distribution characteristics of the welding points are further clarified, and the even distribution of the welding points helps to ensure the structural stability of the double-layer pipe during the welding process. Since the welding points act evenly on the entire welding area, the local stress concentration or deformation caused by the uneven distribution of the welding points is reduced, thereby improving the overall stiffness and deformation resistance of the welded structure. Evenly distributed welding points help to achieve uniform heat transfer, which is crucial to prevent thermal deformation during welding. During the welding process, the concentration of heat may cause uneven expansion and contraction of the material, thereby generating internal stress and cracking. By evenly distributing the welding points, the temperature distribution of the welding area can be more effectively controlled, reducing the risk of thermal deformation and cracking. In addition, evenly distributed welding points also help to improve the quality and consistency of the welded joint. Due to the even distribution of the welding points, the welding material can fill the weld more evenly, thereby improving the integrity and uniformity of the weld, and enhancing the bearing capacity and durability of the welded joint. Compared with the common solution of unevenly distributed welding points, the present invention effectively solves the problems of stress concentration, thermal deformation and inconsistent quality of the welded joint that may occur during welding by evenly distributing the welding points.

[0040] In this embodiment, the welding process includes laying the double-layer pipe flat, then selecting one end for welding. After completing the welding of one end, move to the other end and repeat the same welding steps.

[0041] The welding process begins by laying the double-layer pipe flat and selecting one end for welding. After completing the welding of one end, the double-layer pipe is moved to the other end and the same welding steps are repeated. This method allows the operator to perform the welding work in an orderly manner, ensuring that each end undergoes the same welding process, thereby ensuring the consistency and reliability of the welding quality. The straight-through welding tool X is inserted into the groove of the upper flange C or the lower flange D (step d). Next, the straight-through welding tool X is used to weld from the groove, while the peripheral welding tool Z is used on the outside to form simultaneous melting of the inside and outside (step e). This step is to achieve simultaneous melting of the inside and outside, which helps to improve the strength and quality of the weld while reducing welding stress and potential cracking risks. After welding a section, the straight-through welding tool X is pulled out of the current groove and then inserted into the adjacent groove to continue welding the next section. This segmented welding method not only improves the flexibility of operation, but also makes the welding process more refined and controllable. This welding method achieves effective control of the welding quality of the double-layer pipe through an orderly welding sequence and precise operating steps. The strategy of laying flat for welding and moving sequentially, combined with the technology of simultaneous melting of the inside and outside, not only improves the stability and consistency of welding, but also reduces the risk of cracking by reducing welding stress, thereby improving the overall structural strength and durability of the double-layer pipe.

[0042] The welding process in step c further includes: d: Insert the straight welding tool X into the groove of the upper flange C or the lower flange D; e: Welding is performed from the groove using the straight-through welding tool X, while the peripheral welding tool Z is used on the outside to achieve simultaneous melting of the inside and outside.

[0043] After welding a section, the through welding tool X is pulled out from the current slot and then inserted into the adjacent slot to continue welding the next section.

[0044] This method requires the operator to pull out the straight-through welding tool X from the current slot after welding a section, and then quickly insert it into the adjacent slot to continue welding, thereby achieving an efficient and continuous welding process. This mode of operation not only improves the efficiency of welding, because it reduces the time for tool replacement and repositioning, but also ensures the consistency of welding parameters, which helps to maintain the uniformity and stability of the welded joint. Through segmented welding, the welding area is allowed to cool gradually, which reduces the welding stress concentration that may be caused by rapid overall heating and helps to prevent cracking during welding. In addition, this method provides greater flexibility and controllability, allowing the operator to flexibly adjust the order and progress of welding according to specific welding needs and pipe characteristics. This method is also highly adaptable and suitable for double-layer pipes of different lengths and shapes, because it allows the welding strategy to be adjusted according to the specific conditions of welding. It significantly improves the efficiency of the welding process and the quality of the welded joint, reduces the labor intensity of the operator, and extends the service life of the double-layer pipe.

[0045] The welding tools include straight-through welding tool X, curved welding tool Y and peripheral welding tool Z, which are designed for specific welding tasks. The straight-through welding tool X and the peripheral welding tool Z are designed in the same way, and the designers pursue standardization and interoperability between the tools to simplify the operation process and improve the versatility of the tools. This design allows operators to flexibly switch between different welding applications while maintaining consistency and efficiency in operation. Further, an important feature of the welding tools is that they all include detachable welding gun barrels. This design provides great flexibility and adaptability because the welding gun barrel can be replaced with different cross-sectional shapes such as round, square, rectangular and special shapes according to different welding requirements. This diversity enables the welding tools to adapt to various welding environments and material requirements, thereby expanding their application range. In particular, the introduction of detachable welding gun barrels allows the tools to be optimized according to specific welding tasks, for example, selecting a specific cross-sectional shape to match a specific welding area, or selecting the most suitable welding gun barrel according to the heat conduction characteristics of the welding material. This not only improves welding efficiency, but also helps to ensure the quality of the welded joint and reduce the risk of welding defects. In addition, this detachable design also facilitates the maintenance and cleaning of welding tools, extending the service life of the tools. By simply replacing the welding gun barrel, the operator can quickly switch between different welding tasks without having to replace the entire welding tool, which greatly improves the convenience and economy of operation.

[0046] In this embodiment, a detailed operation process is described, from the preparation stage to the completion of welding, and each step is carefully designed and considered.

[0047] The initial stage of the operation involves laying the double-layer tube flat and fixing it to ensure the stability of the welding operation. At this stage, the layout of the welding points needs to be uniform to ensure uniform heating and structural stability during the welding process. Next, for the upper flange C or lower flange D, according to the specific needs of welding, an appropriate number and shape of grooves are opened to provide access for the welding tool. The design of the groove is a key step to achieve simultaneous melting of the inside and outside, and needs to be carefully calculated and set according to the geometric characteristics of the double-layer tube and the specific needs of the welding part.

[0048] In terms of the selection and use of welding tools, the present invention provides a straight welding tool X and a peripheral welding tool Z, which can be adapted according to the shape and position of the welding part. The straight welding tool X is suitable for the straight welding groove between the inner tube A and the outer tube B, while the peripheral welding tool Z is suitable for the outer side welding of the outer tube B. The design of these welding tools allows them to adapt to pipes of different shapes and sizes, including round, square, rectangular and special shapes, providing a high degree of flexibility and adaptability.

[0049] The welding process itself requires precise control of welding temperature and speed to ensure that the welding materials are fully melted and form high-quality welds. The welding tool heats the welding part through a high-temperature flame to achieve simultaneous melting of the inside and outside. This innovative bilateral melting technology is the core of the present invention and can effectively eliminate welding defects and cracking hazards. After completing the welding of one end, the operator needs to quickly pull the welding tool out of the current slot and insert it into the adjacent slot to continue the next section of welding. This segmented welding strategy helps to maintain the continuity of the welding process while reducing welding stress and cracking risks caused by heat concentration. In the process of implementing the present invention, issues that need to be paid attention to include ensuring the cleanliness and safety of the welding environment, monitoring the welding temperature and speed, and correctly selecting and using welding tools. In addition, the reasonable arrangement of the welding sequence is also a key factor in ensuring welding quality.

[0050] The preferred solution of the present invention also includes a detachable design of the welding tool, which can quickly replace the welding gun tube according to the specific welding task, improve welding efficiency and facilitate maintenance. The design of the welding tool can be adjusted according to different welding environments and material properties to adapt to pipes of different shapes and sizes.

[0051] According to the above processing method flow, it can be known that the core principle of the double-layer tube combined welding method of the present invention is to achieve uniform penetration of the weld part through bilateral melting technology, thereby eliminating welding defects and cracking hazards. This method is applicable to various types of double-layer tube structures, not only limited to circular ones, but also square, rectangular and special-shaped structures. The key point of the welding process is to form a closed or semi-closed space between the inner tube and the outer tube, and by grooving at the appropriate position, the special welding tool can penetrate into the interlayer and melt the welding part from the inside and outside at the same time.

[0052] First, the welding method begins by using several welding points to form a preliminary fixing structure between the inner tube A and the outer tube B. These welding points are evenly distributed between the upper flange C and the outer tube B and between the lower flange D and the outer tube B, ensuring the stability and uniform heating of the double-layer tube during the welding process. The role of the preliminary fixing structure is to provide a solid foundation for subsequent welding work and prevent deformation or displacement caused by thermal expansion or other external forces during the welding process.

[0053] Next, several grooves are opened on the upper flange C or lower flange D of the inner tube A. The design of these grooves is crucial because they are the channels for the welding tools to be inserted. The shape, size and position of the grooves are carefully designed to ensure that the welding tools can reach the welding part smoothly. The design of the grooves must take into account not only the geometry of the inner tube, but also the operating space of the welding tools and the flexibility during the welding process.

[0054] During welding, use straight welding tool X or curve welding tool Y, and select according to the shape of the product and the slot position. Straight welding tool X is suitable for straight welding slots, while curve welding tool Y is suitable for curved welding slots. The length, curvature and other parameters of these welding tools can be adjusted according to specific welding requirements to ensure the accuracy and effectiveness of welding.

[0055] The design of the welding tool allows it to adapt to tubes of different shapes and sizes, including but not limited to round, square, rectangular and special-shaped tubes. The welding tool includes a detachable welding gun tube, and the cross-section of the welding gun tube can be round, square, rectangular and special-shaped to adapt to different welding environments and material properties. This design not only provides a high degree of flexibility and adaptability, but also facilitates the maintenance and cleaning of the welding tool. During the welding process, the welding tool is inserted from the groove to achieve simultaneous melting of the inside and outside. This bilateral melting technology is the core innovation of the present invention, which effectively reduces the risk of internal stress and cracking during the welding process. By heating the inside and outside at the same time, the weld is formed more evenly, thereby improving the quality of the welded joint and the stability of the overall structure.

[0056] The welding method also includes the optimization of the welding sequence. First, lay the double-layer pipe flat, select one end for welding, and after completing the welding of one end, move to the other end and repeat the same welding steps. This sequential welding method ensures the continuity and consistency of the welding process and avoids welding defects caused by improper welding sequence.

[0057] In addition, in this embodiment, the welding method also emphasizes the continuous use and movement of the welding tool. After completing a section of welding, the welding tool is pulled out of the current slot and then inserted into the adjacent slot to continue the next section of welding. This segmented welding strategy improves the flexibility and controllability of welding, while also reducing welding stress and preventing cracking during welding.

[0058] Compared with the traditional single-sided welding method, the double-sided melting technology of the present invention significantly improves the welding quality and reduces the risk of cracking. In addition, the welding method of the present invention has high adaptability, can meet the needs of different types of double-layer pipe welding, and has broad application prospects.

[0059] In summary, the double-layer pipe combined welding method of the present invention realizes an efficient and high-quality welding process through bilateral melting technology, carefully designed welding tools, optimized welding sequence and segmented welding strategy. This method not only improves the overall performance and service life of the double-layer pipe, but also has significant innovation and practicality, providing a more reliable and efficient solution for the double-layer pipe welding field.

[0060] It is worth noting that when welding the upper flange C and the outer tube B, the curved welding tool Y is used instead of the straight welding tool X. The length and curvature of the curved welding tool Y are selected according to the product diameter and position. After welding a section, the curved welding tool Y is pulled out of the current slot and then inserted into the adjacent slot to continue welding the next section.

[0061] In the preparation stage, we precisely place the double-layer pipe combination on the welding workbench to ensure that the relative position of the inner pipe A and the outer pipe B is accurate, laying a solid foundation for subsequent welding. Next, according to the specific shape of the product and welding requirements, slots are opened at appropriate positions of the upper flange C or lower flange D of the inner pipe A. These slots are the key channels to achieve full penetration of the weld. It is crucial to choose the right welding tool. The straight welding tool X and the curved welding tool Y are carefully selected according to the shape and position of the slot to ensure that they can penetrate deep into the interlayer and heat the welded part from both the inside and the outside.

[0062] The start of the welding process requires the operator to adjust the welding equipment to the appropriate temperature and flow rate to ensure that the welding torch flame is uniform and stable. In this embodiment, the double-layer pipe assembly welding is mainly composed of an inner pipe A, an outer pipe B, an upper flange C, and a lower flange D. Figure 2 As shown. The upper flange C and the lower flange D are first welded to the inner tube A. The inner diameter of the outer tube B is larger than the outer diameter of the upper flange C and the lower flange D (i.e., a welding gap is left). The implementation steps are as follows: Weld the upper flange C and the lower flange D to the inner tube A respectively; Several grooves are opened on the upper flange C and the lower flange D respectively (the number of grooves is determined by the product diameter and process, and 8 grooves are opened on each flange in this example) for passing the welding gun (and other parts, if any); Assemble the inner tube A and the outer tube B together vertically according to the requirements of the drawing; Spot weld several welding points between the upper flange C and the outer tube B, and spot weld several welding points between the lower flange D and the outer tube B; make the inner tube A and the outer tube B relatively firm; in this example, there are 8 welding points.

[0063] Lay the double-layer pipe flat and choose any end to weld first. In this example, choose to weld the lower flange D and one end of the outer pipe B first. Pass the straight welding tool X through the groove of the upper flange C until it reaches the welding position of the lower flange D and the outer pipe B. At the same time, on the outside of the welding part, another welding gun Z starts welding, forming a double-sided melting state inside and outside with the straight welding tool X. The length of the straight welding tool X is appropriately designed according to the length of the outer pipe B, with the principle of easy operation.

[0064] According to the operation method of step 5, after welding a section, take out the straight welding tool X from the first groove, pass it through the second groove of the upper flange C until it passes through the welding part, and then weld the next section. Repeat this step until the lower flange D and the outer pipe are welded for a whole circle.

[0065] According to steps 5 and 6, the upper flange C and the outer tube B are welded using a curve welding tool Y. The curve welding tool Y needs to be designed according to the diameter and position of the product, with the principle of easy operation. According to the operation method in step 7, after welding a section, take out the curve welding tool Y from the first slot, pass it through the second slot of the upper flange C until it reaches the welding part, and then weld the next section. Repeat this step until the upper flange C and the outer tube B are welded for a full circle.

[0066] After the welding is completed, there is still one last slot that has not been welded through the curve welding tool Y. At this time, the curve welding tool Y is taken out and the slot is welded to complete the entire welding process.

[0067] After welding is completed, the operator will turn off the welding equipment and cool and clean the welded parts, followed by necessary post-processing, such as removing welding slag and stress relief, to ensure the quality and performance of the welded joint. Throughout the implementation process, we pay special attention to the precise design of the notch, the correct selection and adaptation of welding tools, the timely adjustment of welding parameters, and the control of the welding environment, which are important factors affecting welding quality.

[0068] This method introduces a curve welding tool Y, the length and curvature of which can be adjusted according to the diameter and position of the product. The use of curve welding tool Y can better adapt to different welding environments, especially in the welding of flange C, it can fit the curve shape of the flange, ensure the uniform distribution of heat during welding, thereby reducing welding stress and improving weld quality. During the welding process, after completing a section of welding, the curve welding tool Y will be pulled out of the current slot, and then quickly inserted into the adjacent slot to continue the next section of welding. This method improves the efficiency and continuity of welding, while maintaining the consistency of welding parameters, ensuring the uniformity and stability of the welded joint. This segmented welding strategy allows the welding area to cool gradually, further reducing welding stress and preventing cracking that may be caused by rapid overall heating.

[0069] In addition, the use of the curved welding tool Y reflects the flexibility and accuracy of the present invention in the field of welding. It is not only suitable for flanges C of different diameters and shapes, but also improves the overall performance and service life of the double-layer pipe by reducing the thermal impact during the welding process.

[0070] In this embodiment, the welding tools include a straight welding tool X, a curved welding tool Y and a peripheral welding tool Z, and the straight welding tool X and the peripheral welding tool Z have the same structure. The welding tools all include a detachable welding gun tube, and the cross section of the welding gun tube includes but is not limited to round, square, rectangular and special-shaped.

[0071] In particular, the structural features of the curved welding tool Y are crucial in the design of the welding utensil to adapt to different welding needs. The design of this tool allows it to fit the specific shape of the welding area, especially when the welding area is curved or has an irregular shape. The curved shape of the curved welding tool Y is able to reach deep into the welding groove, ensuring the uniformity and continuity of the welding process, especially in scenarios where circumferential welding or welding on curved surfaces is required. The structural design of the curved welding tool Y takes into account the heat distribution during the welding process and the fluidity of the welding material. By optimizing the shape of the tool, it can better control the welding heat and reduce the unnecessary impact of heat on the surrounding materials, thereby reducing the risk of welding deformation and stress. In addition, the curved welding tool Y is able to improve the filling efficiency of the weld because its shape is more suitable for following the welding path and ensuring the uniform formation of the weld. With a variety of welding utensil structures, operators can cope with complex welding tasks more flexibly, whether in straight or curved welding areas.

Claims

1. A welding method for preventing a double-layer pipe assembly from cracking immediately, characterized in that: The following steps are involved: a: Use several welding points to form a preliminary fixing structure between the inner tube A and the outer tube B; b: Several grooves are provided on the upper flange C or the lower flange D of the inner tube A to insert the straight welding tool X; c: Use the straight-through welding tool X and the peripheral welding tool Z on the outside of the outer tube B to weld at the connection between the upper flange C or the lower flange D and the outer tube B.

2. The method according to claim 1, characterized in that The welding points are evenly distributed between the upper flange C and the outer tube B and between the lower flange D and the outer tube B.

3. The method according to claim 1, characterized in that The welding process involves laying the double-walled tube flat and then selecting one end to weld.

4. The method according to claim 3, characterized in that After completing the welding on one end, move to the other end and repeat the same welding steps.

5. The method according to claim 1, characterized in that The welding process in step c further includes: d: Insert the straight welding tool X into the groove of the upper flange C or the lower flange D; e: Welding is performed from the groove using the straight-through welding tool X, while the peripheral welding tool Z is used on the outside to achieve simultaneous melting of the inside and outside.

6. The method according to claim 5, characterized in that After welding a section, the through welding tool X is pulled out from the current slot and then inserted into the adjacent slot to continue welding the next section.

7. The method according to claim 1, characterized in that When welding the upper flange C and the outer pipe B, a curved welding tool Y is used instead of a straight welding tool X. The length and curvature of the curved welding tool Y are selected according to the product diameter and position.

8. The method according to claim 7, characterized in that After welding one section, the curve welding tool Y is pulled out from the current slot and then inserted into the adjacent slot to continue welding the next section.

9. A welding tool for performing the welding method for preventing instant cracking of a double-layer pipe assembly according to any one of claims 1 to 8, characterized in that: The welding tool comprises a straight-through welding tool X, a curved welding tool Y and a peripheral welding tool Z. The straight-through welding tool X and the peripheral welding tool Z have the same structure.

10. The welding tool according to claim 9, characterized in that: The welding tools all include a detachable welding gun tube, and the cross section of the welding gun tube includes but is not limited to round, square, rectangular and special shapes.

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